I actually finished this book a while ago, but have been putting off reviewing as I am not sure what I think of it...
I think my main problem with it was that when I read what the book was about before I started reading it, it actually looked like it was a different story. Turns out that it was describing the first Bioshock game, not the book! (I think this has been corrected now.) So when I started reading it got a little confusing, and it took me a while to 'readjust' to what the story was about.
I enjoyed reading about how everything was created and what happened before the Bioshock games though! I found the first half of the book was quite slow going, but it picked up a bit towards the end. I think they could have made a lot more out of the story, so I was a little bit disappointed.
I would recommend this book to Bioshock fans that are interested in how Rapture came to be :)